PRODUCT AND PROCESS DEVELOPMENT L. J., and Spadaro, J. J., J . Am. Oil Chemists’ SOC.,30, 139-43
literature cited
(1953). (8) Persell, R. M., Pollard, E. F., Deckbar, F. A., Jr., and Gastrock, E. A., Cotton G i n & Oil Mill Press, 53, No. 17, 18, 20 (1952). (9) Pominski, J., Eaves, P. H., Vix, H. L. E., and Gastrock, E. A., J . Am. Oil Chemists’ Soc., 31, 451-5 (1954). (10) Sayre, J. E., and Marsel, J., Chem. V e e k , 71, No. 13, 29-50 (1952). (11) Spilsbury, C. C., “Marketing and Processing Costs of Cottonseed Oil Mills in the Post War Period, 1946-7 to 1950-1,”p. 32, U. S. Dept. Agr., Production and Marketing Adm., Fats and Oils Branch, Washington 25, D. C., 1952.
(1) Andrews, J. P., and Kurtz, A. E., Cotton G i n & Oil Mill Press, 54, NO.24, 12, 13,37-8 (1953). (2) Brewster, J. M., “Comparative Economies of Different Types of
Cettonseed Oil Mills and Their Effect on Oil Supplies, Prices, and Return to Grower” U. 5.Dept. Agr. Marketing Research Rept. 54, 107-9 (1954). (3) Chilton. C. H.,Chem. Eng., 56, No. 6, 97-106 (1949). (4) “Data and Methods for Cost Estimation; A Collection of Articles from Chemical Engineering,” McGraw-Hill, New York, 1946-52. (5) Gastrock, E. A.,Persell, R. M., and Pollard, E. F., Cotton Trade
J.,34, No. 49, 6 (1952). (6) Gastrock, E. A., Spadaro, J. J., Gardner, H. K., Knoepfler, N. B., and Molaison. L. J., Oil Mill Gaz., 59. No. 2. 40-1
RECEIVED for review December 9,1954. ACCEPTED March 26, 1955. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture. Presented a t the Southeastern Regional Meeting, ACS, Birmingham, Ala., October 21, 1954.
(1954). (7) Graci, A. V., Jr., Reuther, C. G., Jr., Eaves, P. H., Molaison,
Ozonolysis of Alpha-Pinene FRANK HOLLOWAY’,
H.
JOYCE ANDERSON, AND WALTER RODIN
Armour Research Foundation o f Illinois Instifufe of Technology, Chicago 16, 111.
T
-
HE discovery that the esters of pink acid (2,2-dimethylby the ozonolysis of a-pinene in the liquid phase using concentrations of ozone up to 100%. The structural formulas of the 3-carboxy-cyclobutylacetic acid) have excellent lubricant (8) and plasticizer (3, 6 ) properties has stimulated interest in this principal compounds are compound and in its precursor, pinonic acid (2,2-dimethyl-3acetylcyclobutylacetic acid). The cost of producing these acids by permanganate oxidation of a-pinene to pinonic acid and furtheis oxidation to pink acid with hypochlorite is expensive. On the other hand, an ozonolysis process might be developed 02* which would be economically attractive. Harries and coworkers (6)made a cursory investigation of the ozonolysis of a-pinene and reported about 25% yields of a liquid pinonic acid. Subsequently Brus ( 9 ) obtained low yields of solid optically active pinonic acid PINENE PlNONlC ACID PlNlC ACID by decomposition of an ozonide of a-pinene. More recently, Spencer and coworkers (9) have reported that vapor phase ozonization of aTable I. Effects of Solvents and Post-OzonizationMethods on Pinonic and Pinic Acids Yields pinene yields an ozonide conOzonization Conditions taining five atoms of oxygen Pinene 10 ml. Carrier gas Nitrogen which yields pinonic acid. Ozone a t 10% level 1 gram Fritted glass pencil gas dispersion unit They question the validity Ozone a t 5 % level 0 . 5 gram Ozone flow rate 10 l./hr. of Harries identification of Ozonization Oa pinonic acid. Post-Ozonization mole Temp., Yielda, Prior to the initiation of Method Solvent MI. % c. % Special Conditions the research reported here, Standard aq. HzOz added, Acetic acid 30 10 25 46,49b Oz carrier gas refluxed 2 hr. Acetic acid 20 10 25 315 Perforated glass tube gas workers at the Naval Stores He0 1 dispersion unit in pinene phase; 50 ml. Station of the United States Acetic acid 26 10 0 27 pinene Department of Agriculture, Methyl alcohol 4 Acetic acid 30 10 25 23 Southern Utilization ReIDreozonizedl search Branch, had verified Acetic acid 28 10 25 33 Acetic anhydride 2 the fact that pinonic acid is Reduced in volume to CCL 30 5 25 58b actually obtained by liquid about 5 ml. by heating CClr 30 5 25 68,666 over water bath and then 2 phase ozonolysis of a-pinene refluxed 2 hr with standacid 30 5 2 5 50 ard HzOz -’ CHICOOH ~ ~ acid ~ ~ 2 i c using low concentrations HzO solution (295) of ozone ( 4 ) and had Ethyl acetate 30 5 25 24 increased the yield of pinonic Ethyl alcohol 30 5 0 14 Methyl alcohol 30 5 -12 51b acid to about 5070. This Chloroform 30 5 0 53 Perforated glass tube diswork consists of a broad Acetic acid 2 persion unit 30 10 25 276 Total ozonized system Nitro methane screening program of the heated for 5 hr. over 25 28 effect of a number of variwater bath and then H ~ ~ ~ ~ ~ l u 30 o r o lo vigorously refluxed 2 hr. 2 ables on the production of withstandard HnOt-CHs30 5 25 36 COOH-Hz0 solution pinonic acid and pinic acid Acetic acid 2
8 bo*” 6
2:k:
1
Present address, Air Products,
October 1955
:;r
a Combined percentage yield of pinonic acid and pinic acid based on amount of ozone used. acid to pinic acid approximately 9:l. b Best of multiple runs.
INDUSTRIAL A N D ENGINEERING CHEMISTRY
Ratio of pinonic
2111
PRODUCT AND PROCESS DEVELOPMENT Table II.
Effect of Gaseous Ozone Concentration on or-Pinene Concentration
Ozonization Contacting Concentration, Mole % 0: NZ Oz method Fritted glass pencil near 7.5 92.5 bottom of reactor 7.5 92.5 15 85 100
Introducing gas over continually stirred (magnetic) surface
Tirpe, Yield, min. %" 25 56 (51) 55 (4j) 25 59 (55) 12 47 (45). 52 (46) 60 56 (53) '
60
100
52 (49), 53 (47) 55 (50)'
60 54 (45) Capillary bubbler near 100 bottom of reactor a Combined percentage yields of pinonic acid and pinic acid based on amounb of pinene used. Number in parenthesis is percentage yield of pinonic acid alone.
Effect of solvent, ozone concentration, and temperature on yields were investigated Solvent Screening. The data obtained from an evaluation of the effect of solvent are listed in Table I. Except for those from experiments involving the use of acetic acid and carbon tetrachloride-acetic acid as solvents, all data in Table I resulted from single experiments, unless otherwise indicated. The best of several experiments with each of five selected solvents, involving changes in concentration of ozone, ratio of ozone to pinene, and ozonization temperature, are listed in Table I with the footnote about multiple runs. I n view of the apparent superiority of the carbon tetrachloride-acetic acid solvent system, this system was investigated in some detail. Ozone Concentration. The ozonization of a-pinene in carbon tetrachloride-acetic acid solvent was studied as a function of ozone concentration in order to ascertain the possible advantages of the use of high concentrations of ozone. The technical literature does not contain any references to the use of high concentrations of gaseous ozone in the controlled oxidation of organic compounds. A series of ozonolyses was made with 7.5, 15, and 100 mole % gaseous ozone during the ozonization phase, followed by a 0.5hour reflux treatment. The data for these runs are presented in Table 11. The fact that the yields for all these runs are so nearly the same strongly suggests that the yield of desired products is independent of the concentratiqn of gaseous ozone used. Effect of Temperature. The effect of temperature on the ozonization of pinene in carbon tetrachloride-acetic acid solvent was investigated. These data, comprising a part of Table I11 suggest that there is only a slight increase, if any, in the yield of pinonic acid caused by changing the temperature of ozonization from 25' to 5' or -40' C. Carbon tetrachloride-acetic acid solvent composition and ratio of pinene to ozone during ozonization do not substantially affect yields The data acquired on the effects of solvent composition and the ratio of pinene to ozone on the ozonization of pinene in carbon tetrachloride-acetic acid solvent is presented as part of Table 111. These data suggest that changes in these variables do not effect any pronounced changes in the yield of pinonic acid. It appears that slightly better yields are obtained when a large excess of ozone is used. Post-Ozonization Use of Dilute Ozone. An investigation was made of the post-ozonization use of a very dilute ozone (1000 p.p.m.) in oxygen at the reflux temperature of the liquid phase, 2112
compared with simple refluxing. The data for these experiments are listed in Table IV. I n five of the six comparisons made between the use of simple refluxing and the use of 1000 p.p.m. ozone, the use of ozone slightly increased the yield of desired products. The results of three series of experiments, designed to test the effect of using dilute ozone over a long period of time, suggests that little or no increase in the yield of desired products is obtained by using 1000 p.p.m. ozone for more than 2 hours. The results of a single pair of experiments, designed to explore the advantages of using more concentrated ozone for post-ozonization treatments, suggests that the use of 2000 p.p.m. ozone may be more beneficial than 1000 p.p.m. ozone. Experimental conditions are discussed
Analysis for Products. An aliquot of the final ozonolysis system, stripped of solvent, was dissolved in chloroform and chromatographically analyzed by the method of Marvel and Rands (7). Identification of the leading peak eluant volume sequence a5 pinonic acid, terebic acid, and pinic acid, respectively, was made on the basis of unpublished studies conducted in the laboratories of the Naval Stores Research Division of the United States Department of Agriculture, Olustee,Fla., and our own study of known mixtures of pinonic acid, terebic acid, and pinic acid. The percentage of butanol in chloroform for the three elution solvents used were 0, 1, and 2, respectively. To each 10-ml. fraction eluted, 15 ml. of 95% ethanol was added prior to titration with standard alkali to the phenol red end point. Ozonization with Dilute Ozone. Dilute ozone of known concentrations was prepared by vaporizing a known quantity of 100% liquid ozone in an evacuated reservoir of known volume and adding pure nitrogen or pure oxygen until 2 atmospheres pressure (absolute) was obtained. A given amount of the dilute ozone was then bled through a grooved stopcock and rotameter a t 10 liters per hour through the reactor containing the solution of pinene. The reactor (for runs with an excess of pinene over ozone) was essentially a 28 X 200 mm. test tube with a short 45' side arm about 125 mm. above the bottom of the reactor, with a 24/40 standard taper joint permitting connection with a reflux condenser and exhaust gas tube. An 8-mm. outside diameter glass gas inlet tube was concentrically sealed to a male 24/20 standard taper joint which fitted the top of
Table 111. Effects of Varying Certain Ozonization Conditions on Yield of Pinonic Acid Os passed over constantly stirred surface of reaction charge) Reaction Charge ~~l~ Av. Acetic Ratio Temp., Pinene, CCL, acid, Pinene: Yield, * E 0 C. grams ml. 01 %" Remarks ml. 25 3.4 330 20 6:lO 59 3.4 330 20 6:lO 49 3.4 330 20 6:lO 48 20 9:lO 45 A flocculent-gummy 25 5.1 330 5.1 330 20 9:lO 44 precipitateformed 10 9:lO 44 during ozoniza5.1 330 tion on warming the gelatinous ma: terial formed an oil strongly adheient t o glass which dissolved i i the solvent after several minutes a t 750 c. 25 4.8 790 10 8.5:lO 44 (2 grams of 100%
5
3.4 5.1 5.1
330 330 330
10 10 30
6:lO 9:lO 9:lO
52 43 49
-40 5.1 330 30 9:lO 50 Per cent of theoretical yield of pinonic acid obtainable from amount of pinene charged, assuming 100% pure a-pinene. Common post-ozonization treatment with 1000 p.p.m. 0s a t 75O C. for 2 hr.
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 47,No. 10
PRODUCT AND PROCESS DEVELOPMENT
Table IV. Run NO.
Aliquot
1-6C
1st 0.5
1.0
7c
8
Effects of Post-Ozonization Treatment with Dilute Ozone in Oxygen
A
B C
1.0 1.0 1 .o
(Ozonizations run with 100% Or) Reflux, Hr. Pinonic Combined Acid Yield, Percentage, With 0 8 , P.P= 1000 2000 %" Yield b 47.5 lt1.7 52.3 f2.1 1.0
53
61
1 .o 2.0
50 54 57
55
61
Remarks Three sets of runs a t 7 . 5 , 15,and 100% 01,each set in duplicate Repeating ozonization conditions of Run 7
contacts the substrate at a single but continuously renewed gas-liquid interface. The ozone can also be introduced beneath the surface of the reaction charge. The time required for the vaporization of the liquid ozone may be varied by controlling the rate of vaporization of the refrigerant.
Post-Ozonization Use of Hydrogen Peroxide. I n the postozonization use of hydrogen 56 64 A 0.5 10 peroxide, the initial composiB 2 :0 59 68 tion of the aqueous phase was 2.0 A 49 57 Repeating ozonization conditions 11 30 ml. of acetic acid, 20 ml. of B 4.0 57 47 of Run 10 water, and 10 ml. of 30% hy6.0 C 50 57 drogen peroxide for each gram 48 A 2.0 Repeating ozonization conditions 12 of ozone passed through the 48 B 4.0 of Run 10 reactor. After 1 hour a t reflux 46 C 8.0 temperature, 20 ml. of 30% A 0.5 38 13 hydrogen peroxide was added i.'5 45 B and the system was held a t 40 A 0.5 Repeating ozonization conditions 14 reflux temperature for a second 44 B 2.0 0.5 of Run 13 hour. 3.0 48 C 0.5 Post-Ozonization Use of 0.5 D 5.0 48 Dilute Ozone. I n the postA 2.0 50 I5 ozonization use of very dilute 56 61 B 2.0 2.0 ozone in oxygen a t the reflux 2.0 2.0 64 56 16 temperatureof the li uid phase, the ozone was introjuced new 45 48 A 0.5 10% Ozone 17 the bottom of the solution B 2.0 52 58 through a thick walled capila Percentage yield of theoretical based on pinene charged. lary tube a t the approximate b Combined percentage yield of pinonic acid and pink acid based on pinene. C Mole ratio of pinene t o ozone 6: 10; 0.85 gram pinene, 31. ml. CClr. 8 ml. acetic acid. All other cases involve rate of 4 liters per minute. wide variations in ratio of solvent components and ratios of pinene to ozone. The ozone was produced by an Oxo-Ray ozone generator, and the approximate ozone concentra$ionwas measured by iodometric analysis of the effect of the gas stream on aqueous the reactor tube. The gas inlet tube terminated about 15 mm. potassium iodide. from the bottom of the reactor with a coarse fritted borosilicate Reagents. Pure liquid ozone was prepared by a technique glass pencil, 12 mm. outside diameter, or a finely perforated endsimilar t o that of Brown and Franson ( I ) . The pinene used sealed glass tube. was supplied by the Naval Stores Research Division of the United States Department of Agriculture and was estimated to be During ozonization, the reactor was surrounded by 530 ml. approximately 95y0 a-pinene with hhe major impurity being 8of water (or other appropriate coolant), held in an open widepinene. mouthed Dewar flask. The jacketing water was stirred interAll other reagents used were of the highest grade commercially mittantly during the ozonization period and a temperature rise available. of approximately 4" C. was usually observed for each 0.95 gram Acknowledgments of ozone passed into the reactor. Ozonization with 1 0 0 ~ oOzone. Liquid ozone and high conThe assistance of H. M. Coleman and W. C. Witham in decentrations of gaseous ozone are highly reactive with iron, brass, signing these experiments is gratefully acknowledged. Other mercury, rubber, ordinary greases, and many organic and incoworkers a t the Armour Research Foundation made many organic compounds. Glass, stainless steel, aluminum, concenhelpful suggestions on the handling of pure liquid ozone, especially trated sulfuric acid, and perhalogenated hydrocarbons are comC. E. Thorp, R. F. Remaly, and G. Platz. patible with ozone. Ozone handling apparatus must be cleaned scrupulously before using. literature cited The apparatus for conducting ozonizations with 100% ' ozone is as follows: The liquid ozone tube is connected to one arm of an Brown, C . , and Franson, K . D., J . Chem. Phys., 21, 917 (1953). Brus, G.,Bull. inst. pin, No. 3, 68 (1950). inverted U-tube by a ball and socket joint. The shallow U-tube Conyne, R. F.,and Yehle, E. A., IND. ENQ.CHEX.,47, 853-6 is made of 1-mm. capillary tubing and is approximately 2 ft. (1955). long in the horizontal direction. The other arm of the U-tube Fisher, G. S., and Stinson, J. S., IND. ENG.CHEM.,47, 1569-72 terminates in a male standard taper 24/40 joint concentrically (1955). Harries, C.,and Neresheimer, H., Ber., 41, 38 (1908): Harries, ring sealed about the capillary tube which extends about 3 cm. C.,and Seitz, R., Ann., 410, 22 (1915). beyond the joint. An outlet or exhaust tube, made of 0.5-mm. Loeblich, V. M., Magne, F. C., and Mod, R. R.,IND.ENG.CHEM., capillary tubing, extends from the upper side of the 24/20 joint 47. 855-8 (1955). about a centimeter below the ring seal. Standard round bottom Marvel, C . S., and Rands, R. D., J. Am. Chem. SOC.,7 2 , 2642 (1950). flasks are attached to the 24/40 joint. Murphy, C . M.. O'Rear, J. G., and Zisman, W. A,, IND.ENG. The technique of ozonization is described as follows: Liquid CHEM.,45, 119 (1933). ozone is obtained in a glass tube refrigerated with liquid oxygen. Spencer, C. C.,Weaver, W. I., Oberright, E. A., Sykes, H. J., The ozone tube is connected to one side of the inverted U-tube Barney, A. L., and Elder, A. L., J. Org. Chem., 5, 610 (1940). while under refrigeration. The liquid oxygen is allowed to evapRECEIVED for review September 17, 1954. ACCEPTED August 18, 1955. orate from the open Dewar flask and the liquid ozone vaporizes Work done under contract U. S. Dept. of Agriculture and authorized by slowly. The gaseous ozone travels through the capillary tube Research and Marketing Act of 1946. Contract is being supervised by to a point just above the magnetically stirred reaction system and Southern Utilization Research Branch, Agricultural Research Service. 9C
A B
October 1955
0.5 0.5
2o :
38 34
Porous stainless steel gas dispersion unit used
INDUSTRIAL AND ENGINEERING CHEMISTRY
2113
